Biodegradable nanoporous microspheres by RAFT and photodegradation

Nanoporous disk-shaped particles based on polycaprolactone (PCL) and photodegradable poly(methylvinyl ketone) (PMVK) were synthesized and characterized. In this study, PCL based triblock copolymer was synthesized by RAFT polymerization followed by the fabrication of microsphere by emulsion method. Disk-shaped particles were then prepared by UV-irradiation with the microsphere. In order to polymerize by RAFT method, PCL based macro-CTA(chain transfer agent) was first synthesized by reacting carboxylic acid-terminated CTA with PCL, and used for the synthesis of block copolymer with methyl vinyl ketone(MVK). The morphology of the particles before and after UV irradiation were confirmed by SEM and TEM images and spherical microspheres were changed to disk-shaped forms, owing to collapsing of PMVK moieties by UV irradiation.